This invention relates to navigation systems, and more particularly to a technique for electronically obtaining a perspective display aboard a linearly moving vehicle.
Perspective perception of space is very natural to man. The eye recognizes size, distance and orientation of objects, as well as their spatial arrangement on the basis of angular dimensions. Angular inputs to the brain and a vast amount of stored information permit man to navigate through his three-dimensional environment.
Electronic navigational aids have in many respects improved and supplemented human navigation capabilities, but in general they do not provide information which is optimally interfaced with man's brain. They are not a substitute for perspective vision.
The present invention is a perspective navigation system, which provides basically the same information as vision does. A need for such a system is obvious in several practical situations, such as an aircraft landing under adverse weather conditions. Instrument landing systems are well known and improved versions are presently being developed, but known systems operate on the principle of a glide path and provide measurements of the aircraft deviation thereof.
The system disclosed herein is unlike former navigation systems in that it displays a perspective view of the properly marked runway, similar to the way in which its light markers are visible at night, which offers many advantages. Firstly, a difficulty arises with existing instrument landing systems when a pilot landing his aircraft has to make the transition from his instrument readings to visual perception of the runway in the short time interval before touchdown. Such a transition is eliminated by the present invention. Secondly, the pilot does not only receive at a glance, information on the aircraft position, but also its attitude. Thirdly, the system operates with higher redundancy than present instrument landing systems as it does not simply provide meter readings, but a perspective display of a structure, which must agree with the pilot's memory to be trusted. This will protect against multipath propagation errors from which present instrument landing systems suffer.
In my copending application, filed on even date herewith, there is disclosed a perspective navigation system in which a plurality of sensors detects signals from runway marker beacons and a first detected signal is compared to a reference signal and the other detected signals are compared to the first. However, in the present invention all of the detected signals are compared to a reference signal. In addition, the present invention is based on different mathematical formulas.